1. Technical Field
The present invention relates to a position measuring system and a position measuring method that measure a position and angles of an object (the direction to which an object is directed, and the like) in a three-dimensional space, and a computer readable medium storing a program that causes a computer to execute a process for position measurement.
2. Related Art
As a method for measuring the three-dimensional position of an object, often used is a method of calculating position coordinates of the object by capturing images of the object with two cameras and then employing triangulation using the distance between the cameras as a base line. In a case where a positional relationship between six points arranged in a three-dimensional space is known beforehand, on the basis of an image of the six points captured by a camera, calculation may be performed to obtain the position, defined by the six points, of the object in the three-dimensional space (the three-dimensional position, hereinafter) and the angles (the roll angle, pitch angle, and yaw angle; referred to as the three-axial angles, hereinafter).
However, in a case of reading a symbol for indicating information added to an object, the shapes of the symbol in images to be obtained vary depending on the position and angles of the object in relation to the camera. Such being the case, techniques for identifying the symbol on the basis of a captured symbol image by using a certain geometric invariant, regardless of the position and angles of the object in a three-dimensional space, have been proposed.